The Canadian College of Neuropsychopharmacology (CCNP) is the premier college in Canada for expert knowledge on the pharmacology of brain function. This year’s conference was held in la belle ville de Montréal. Though recent years had a much greater attendance – as the CCNP combined with other groups, such as the Canadian Association for Neuroscience and the Scandinavian College of Neuropsychopharmacology – the quality of talks was still exceptional.
The three day conference began with the Presidential Symposium, which focused on current perspectives on dopamine-glutamate interactions in mood and substance abuse disorders. Susan Sesack talked about anatomical perspectives, as reflected in some of her recent work on midbrain nuclei and the habenula (e.g. here), which was an extension and update of previous work. Marina Wolf and Paul Vezina talked about what we currently know about glutamate and dopamine receptors in the nucleus accumbens/ventral striatum with special reference to their effects on stimulant drugs (e.g. cocaine, amphetamine). The first symposium was closed with a talk by Gregor Hasler who focused on recent neuroimaging data underscoring the role of catecholamines (dopamine and noradrenalin) and glutamate in major depressive disorders in humans.
Other notable symposia included “Rodent ultrasonic vocalizations as an emerging tool in neuropsychopharmacology”, in which John Yeomans and colleagues underscored the increasing need, usefulness, and current limitations to understanding the utterances of rats, and “Serotonin and social behaviour during development and adulthood” in which the young researchers Linda Booij and Marije aan het Rot chaired excellent presentations. Of particular note, Susannah Murphy discussed her recent work supporting the notion that one key action of antidepressant treatments may be to alter emotional biases. For instance, it is well known that patients with major depression are more likely to report neutral stimuli as being negative and that aversive stimuli are deemed highly aversive compared to healthy control subjects.
Finally, plenary lectures by Simon Young and Barry Everitt covered a wide range of the work in their respective fields and raised many interesting questions along the way. Dr Young’s talk on “The neurobiology of social interactions” focused on work related to how increases in serotonin (via tryptophan loading) generally decrease quarrelsome behaviours while increasing one’s agreeableness and the perception of agreeableness in others. He questioned to what degree the results from other studies investigating the effects of acute tryptophan depletion (which results in acute decreases in brain serotonin production) in social cooperation may actually be the result of changes in agreeableness/quarrelsomeness as opposed to the complex social explanations (e.g. alterations in cooperativity) that have been suggested.
Dr Everitt’s talk “From impulsive actions to compulsive habits in drug addiction” reviewed a small portion of his immense body of work focused on drug reward/seeking. His recent work really underscores the need for future research to move beyond simple lesion or local brain explorations and towards the complexities of neurotransmitter interactions and brain circuits across regions. For instance, only by simultaneous lesions of the nucleus accumbens core and injections of dopamine antagonists into the dorsolateral striatum on the other side of the brain was his group able to identify the importance of the ‘spiraling’ striatal-nigro-striatal circuitry on drug (e.g. cocaine) seeking behaviour. Also interesting was the notion that decreased dopamine D2/3 receptors in the nucleus accumbens shell is related to increased impulsivity and predictions of cocaine seeking behaviour, although these factors appear to be independent of dopamine release as a whole or the animal’s natural tendency to respond to novelty.
Overall, with speakers from all over the world, this year’s CCNP conference reflected the immense international advances in neuropsychopharmacology over the past few years. It also underscored the idea that knowledge about neurochemical interactions will be necessary for a full understanding of brain function – well beyond drug addiction alone.
aan het Rot M, Moskowitz DS, Pinard G, & Young SN (2006). Social behaviour and mood in everyday life: the effects of tryptophan in quarrelsome individuals. Journal of psychiatry & neuroscience : JPN, 31 (4), 253-62 PMID: 16862243
Dalley JW, Fryer TD, Brichard L, Robinson ES, Theobald DE, Lääne K, Peña Y, Murphy ER, Shah Y, Probst K, Abakumova I, Aigbirhio FI, Richards HK, Hong Y, Baron JC, Everitt BJ, & Robbins TW (2007). Nucleus accumbens D2/3 receptors predict trait impulsivity and cocaine reinforcement. Science (New York, N.Y.), 315 (5816), 1267-70 PMID: 17332411
Murphy SE (2010). Using functional neuroimaging to investigate the mechanisms of action of selective serotonin reuptake inhibitors (SSRIs). Current pharmaceutical design, 16 (18), 1990-7 PMID: 20370666
Sesack SR, Carr DB, Omelchenko N, & Pinto A (2003). Anatomical substrates for glutamate-dopamine interactions: evidence for specificity of connections and extrasynaptic actions. Annals of the New York Academy of Sciences, 1003, 36-52 PMID: 14684434